2000 Fiscal Year Final Research Report Summary
Comparative study of felsic magmas with explosive or not explosive eruption
| Project/Area Number |
10440141
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geology
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| Research Institution | Shimane University |
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Principal Investigator |
SAWADA Yoshihiro Dept. Geosci., Fac. Sci. & Eng., Shimane Univ., Professor, 総合理工学部, 教授 (80196328)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAYAMA Katsuhiro Dept. Geosci., Fac. Sci. & Eng., Shimane Univ., Associate Professor, 総合理工学部, 助教授 (20243420)
SAMPEI Yoshikazu Dept. Geosci., Fac. Sci. & Eng., Shimane Unive., Associate Professor, 総合理工学部, 助教授 (00226086)
KIMURA Jun-ichi Dept. Geosci., Fac. Sci. & Eng., Shimane Univ., Associate Professor, 総合理工学部, 助教授 (30241730)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Quaternary volcanoes / lava dome / pyroclastic flow / felsic magma / volatile components / organic matter / paleomagnetism / reverse thermoremanent magnetism |
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| Research Abstract |
(1) On the basis of paleomagnetic and petrographical studies, it estimates that the four lava domes of Mt. Sanbe formed at 3.7-3.8 Ka. Hemoilmenite showing self-reversal of thermo-remnant magnetization was found in dacite clasts and lava from Mt. Sanbe and Mt. Daisen.
(2) Laboratory experiments aimed at allowing estimation of emplacement temperatures of pyroclastic deposits flows using H/C ratios of entrained carbonized wood were carried by simulating the thermal conditions in pyroclastic flows. H/C ratios show a strong correlation with temperature. H/C thermometry was tested by natural carbonized woods and paleomagnetic blocking temperatures from Holocene pyroclastic flow deposits. Emplacement temperatures of Taiheizan pyroclastic flow deposits about 5.5km from the conduit of the Sanbe volcano were estimated 530-560℃ by these methods.
(3) Organic matter was found in igneous rocks related to sediments during the generation and ascent of magmas, such as S-type felsic rocks, high Mg andesite, rocks formed by slab melting and sedimentary origin migmatite.
(4) Experiments were carried out to examine transformation of sediment-derived hydrocarbons contained in felsic magma and during its solidification at middle crustal condition. Carbonaceous materials remained in all experimental products, not only as carbonate and graphite but also as solid state hydrocarbon, indicating that polymerization occurred.
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